The brief report on Iraqiya television identified the suspect as Mohammed Rabei, also known Abu Dhar and said he was number four in the organisation.
It gave no further details.
Meanwhile, the Iraqi government is investigating information which claims Jordanian born al-Zarqawi may be hiding out in Iran after hot pursuit by US and Iraqi forces in western Iraq.
The were reports that al-Zarqawi was spotted a few weeks ago in areas close to the Himreen Mountains, 120 km south of Kirkuk and near the border with Iran.
Al-Qaeda in Iraq has been blamed for many of the kidnappings and beheadings of foreign and Iraqi hostages, as well as suicide attacks against police, soldiers and civilians.